Elector pump refrigerating apparatus



Nov. 14, 195o 'w. n. DE may 2,530,293

EJECTOR PUIP REFRIGERATING APPARATUS Filed July `11. '1941' 2 sheets-shut' 1 j Nov; 14, 195o w. H. DE LANCEY Y 2,530,293

` EJECTOR PUK? REF'RIGERATING APPARATUS 4Filed .my 11. 1947 2 sums-snm z We; .Pf-larcceg Patented Nov. 14, l

EJE CTOR PUMP REFRIGERATIN G APPARATUS Warren H. De Lancey, Springfield, Mass., assigner K to Atlantic Development Company, Springfield, Mass., a corporation of Massachusetts Application July 11, 1947, Serial No. 760,201

4 Claims.

, This invention relates to refrigeration apparatus of the so-called vacuum type, employing a centrifugal pump for the compression and circulation of the refrigerant fluid, a portion of the latter being circulated through an ejector or jet exhauster, for the entrainment of vaporized refrigerant drawn from the evaporator or cooling unit of the system.

The principal object of my invention is to simplify andlower the cost of such vacuum type refrigeration systems, and at the same time to improve the operation thereof. This is accomplished as hereinafter described, bythe provision between condenser and evaporator, of a novel and highly effective valve mechanism for controlling the ow of the refrigerant to said evaporator.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, and the advantages attained thereby will be readily understood by those skilled in the art.

In the drawings:

Fig. 1 represents a diagrammatic view of refrigerating apparatus incorporating the present invention therein and showing vcertain of the elements in section.

Fig. 2 represents a vertical sectional view of the centrifugal pump of Fig. 1, taken substantially along the line 2-2 of Fig. 1, and showing also the thermostatic control of said pumps driving motor.

Fig. 3 represents, on an enlarged scale, a longitudinal sectional view showing the detailed construction of the control valve mechanism.

Fig. 4 represents an enlarged scale view of a portion of the valve unit disclosed in Fig. 3.

Fig. 5 represents an enlarged scale view of a portion of a check valve disclosed in Fig. 1.

Referring particularly to Fig. l, the present invention is shown in association with a refrigerator Awhich provides the usual cold box I having a door II removably secured over an opening I2 provided in said box. Disposed within the cold box I0 is an evaporator tank I3 the upper portion of which has connected thereto a low-pressure conduit I4. The lower end of the conduit I4 communicates with a substantially cylindrical housing I of an ejector unit I6 which is connected in series with a centrifugal pump contained within a pump housing Il.

Referring particularly to Figs. 1 and 2, the

above noted centrifugal pump comprises the usual rotatable impeller unit I8 which is mounted upon a shaft I9 journaled in the back Wall of the housing Il. An'electric motor 2l)V is coupled to the shaft I9 for the purpose of driving the impeller in the usual fashion. The centrifugal pump housing Il is formed in the usual manner and is connected with an axial intake conduit 2| and a peripheral discharge conduit 22 which are adapted, respectively, to conduct the refrigerant fluid to the pumps axial intake and to dis-` charge the same from the periphery of the pump under pressure. The centrifugal pump discharge conduit 22 extends from the pump housing I1 and into the ejector housing I5 which is hollow and thereby forms an ejector chamber 23. That portion of the conduit 22 which extends within the chamber 23 is provided with a nozzle portion 24 which is axially aligned with and spaced from the intake portion of the conduit 2| which also extends into the chamber 23. This intake portion of the conduit 2l is formed as an expanding passage or port 25 thereby to form, in conjunction with the nozzle 24 and the chamber, a jet exhauster or ejector. This serves, as is usual in vacuum type refrigerating systems, for the entrainment, via conduit I4, of refrigerant uid that is vaporized in evaporator I3, through heat absorption from box I0, and by virtue of the lowered pressure resulting from such ejector action.

The so-circulated refrigerant, such as Freon 12, is supplied in proper quantities to the evaporator I3, after first passing through a suitable condenser 2l, the latter being connected by a conduit 26 to the pump discharge conduit 22. From said condenser, a conduit 29 leads to the interior of a housing 33 (see Fig. 3) forming part of the special control valve mechanism, designated as a whole by the numeral 28, of my invention. Said valve mechanism,v as hereinafter described in detail has a conduit connection 3l) with the low-pressure line I4 of the system, and a conduit connection 3I with the evaporatorv I3, wherein the liquid refrigerant has a static level substantially as indicated by broken line 32. Fig. 1.

Referring particularly to Fig. 3, there is disclosed, on an enlarged scale, a longitudinal sectional view of the control valve mechanism 28. More specifically, said control valve mechanism is arranged in the substantially hollow cup shaped housing 33, the end portion of which is adapted to be closed over by means of an end cap 34. Bolts 35 (only one of which is shown 3 herein) secure the end cap 34 over the housing 33. Between the nange portions of the housing and the end cap 34 is clamped an external flange portion 39 of one end of a flexible metallic bellows 31. The other end portion of the bellows 31 has an internalflange portion which is braced, or otherwise suitably secured, as at 38, t a hollow thimble member 39.

Formed in the wall portions of the housing 33, and communicating with the hollow interior thereof, are a pair of tapped apertures 40 and 4I the former receiving the conduit 29, and the latter receiving the conduit 3|. Threaded into the inside portion of the aperture 4I is a stud element 42 which is provided with a longitudinal bore 43 communicating at one end directly with the aperture 4|. The other end of the bore 43 is provided with a conical valve seat 44. Cooperating with the valve seat 44 is a conical needle valve element 45, one end portion of which is adapted to be carried by means of an annular plate 45 secured directly over the bottom portion of a cylindrical sleeve 41 which is adapted to surround one end of the stud 42. More specically, the needle valve 45 is provided with a pair of spaced annular grooves 43 and 49, each of which is adapted to receive a snap ring 50. The disk 45 may be suitably brazed to the sleeve 41 and the needle valve 45 is held in position by having one of its snap rings 50 engage a face of the disk 46 and the other snap ring engage the face of a washer I. sandwiched between the washer 5| and the inner portion of the sleeve 41 is a soft rubber washer 52. It is the purpose of this rubber washer 52 to prpvide a resilient mounting in sleeve 41 for the needle valve so that the same will be self-aligning with the valve eat 44.

s Between the closed inner end portion of the thimble 39 and the disk 46 is disposed a compression spring 53 which is adapted normally to bias the needle valve 45 towards the valve seat 44. From this, it will be understood that the needle valve 45 is normally urged towards the valve seat so that the bore 43 in the bellows position shown by Fig. `3 will be shut off from the interior portion of the housing 33. However, it is clear that when operation of the centrifugal pump causes the pressure of the refrigerant fluid to build up within the housing 33, it will be effective to bias the bellows 31 and their attached thimble 39 to the left, Fig. 3, which relieves the pressure of spring 53 on plate 46. At its outer end the thimble member 39 is formed with an internal groove 54Tin which is mounted a washer 55 whose inner periphery is spaced from the peripheral portion of the sleeve 41 so as to permit free passage of fluids from opening 40 to opening 4| by way of apertures 9|, 9| formed in the sleeve 41. It is the purpose of the washer 55 to engage the edge portion of the disk 49 whenever the bellows 31 has been compressed a distance equal to that designated by the letter Y. From this, it will be understood that a further movementl to the left of the bellows 31 will be effective to unseat the needle valve 45 from the valve seat 44 thereby placing the bore 43 in communication with the interior portion of the housing 33 by way of the sleeve apertures 9|, 9| and between the washer 55 and the sleeve 41.

Projecting into the interior portion of the housing 33 from the end cap 34 is a cylindrical extension 56. Threaded into one end of the end cap 34 is an adjusting screw 51, the right-hand end portion of which extends into a chamber 58 provided within the cylindrical member 56. Loosely mounted over one end of the adjusting screw 51 is a cap 59 against which one end of a pressure-regulating spring i0 is adapted to be biased. The other end of this spring 69 engages a second cap 6I which is normally biased against a snap ring 62 which is seated within an annular groove 93 formed about the inner periphery of the chamber 58. The reduced end portion of the thimble 39 is adapted to be biased into engagement with the cap 6I by means of the spring 53.

From the above, it is to be understood that the bellows 31 can be compressed a distance Y, against the action of the spring 69 without moving the needle valve 45, but that any further movement oi' the bellows against the spring 50 will be eiective to shift the needle valve away from the valve seat 44.

Projecting from one face of the end cap 34 is a threaded boss 54 over which may be screwed an acorn nut 95. A gasket 6B may be placed between the nut and a shouldered portion of the end cap thereby to prevent the escape of fluids from the chamber 53. Also, the nut 65 will be eifective to protect the end portion of the adjusting screw 51 thereby to prevent the same from being inadvertently turned. By adjusting the screw 51 towards or away from the spring 50. the pressure of this latter element may be readily varied.

Formed in the end cap 34 is a tapped aperture 61 which communicates directly with the chamber 56. Referring particularly to Figs. l and 3, it is to be understood that the chamber 58 is placed in direct communication with the low-pressure conduit I4 by means of the connecting conduit 30 and that the condenser connection 29 is coupled directly to the aperture 40. Also, it is apparent that the aperture 4| communicates directly with the lower portion of the evaporator I3 by means of the interconnecting conduit 3|.

From the above, it is to be understood that when the centrifugal pump is started up, the

liquid refrigerant will completely ll the condenser 21 and thus enter the housing 33 and surround the exterior of the bellows 31 with the result that it will be eiective to exert a pressure on these bellows tending to move the same in a lefthand direction. However, as hereinabove noted, the bellows 31 and the valve springs 53 and 60 are so designed that they will not permit the valve 45 to open until a predetermined pressure differential exists between the fluids contained within the condenser 21 and the evaporator I3. Nevertheless, as the centrifugal pump continues to run and build up the pressure offthe liquid refrigerant, this pressure will soon become great enough to cause a suicient pressure differential between the internal and external portions of the bellows 31 to shift the same toward the left until the washer 55 of the thimble member 39 bears against the disk 46. This initial movement of the bellows will increase the volumetric capacity of the high pressure side of the present apparaof the bellows 38 will be sufficient to continue to compress the spring 6I) thereby to unseat the needle valve 45 and to place the evaporator I3 in direct communication with the condenser 21. Thus, the liquid refrigerant may pass from the condenser 21 and into the evaporator I3 to replenish the loss of refrigerant from the evaporator. From this, it will be apparent that the needle valve 45 will remain unseated from the valve seat 44 as long as the above noted pressure differential is maintained at a predetermined level. Also, whenever the pressure differential between the high and low pressure sides of the system drops, the needle valve 45 will first close, and thereafter a further pressure drop will cause the bellows to shift to the right thereby to decrease the volumetric capacity of the high pressure side of the system so as to force liquid up into the ejector unit I6 thereby to render the pumping system effective to restore the proper uid pressure.

From the foregoing it will be noted that the control valve mechanism is effective to materially increase the volume of the high pressure side of the system before the valve 44 can open to permit the refrigerant to pass into the evaporator I3, this enabling the system to be operated without any necessity for providing `a tank for the storage under pressure of the refrigerant. In this connection it is to be understood that the efficiency of a centrifugal pump depends upon the specific gravity of the fluid being pumped. Thus, such a pump functions well on liquids, but is very sensitive to gas. In other words, the presence of gas in the regenerative system of the present invention causes a sharp drop in the pressure.

In the operation of the here disclosed system, the ejector I6 will draw vaporized refrigerant in considerable quantities from the evaporator I3. Thus, during the continued operation of the centrifugal pump, there is always a tendency for it to draw in much more vapor than can be condensed before the pump inlet is reached, and under these conditions the pressure would drop sharply and the pumping action would slow down or practically cease. In the vacuum refrigerating systems of the prior art, this condition has necessitated the provision of large tanks for the accumulation and storage under pressure of the refrigerant, to permit the vaporized portions of same to separate from the liquid portions; without such tanks there would be no way to fill the regenerative system with liquid and thereby restore the pressure during the operation of the centrifugal pump. But in the vacuum system of my invention, the control valve mechanism 28, by its ability above described to increase the volume of the high pressure side of the system before the valve can be opened, enables such accumulator and separating tanksv to be dispensed with. That is to say, in my improved system, whenever the pressure drops due to the fact` that the pump is handling too much vapor, the discharge valve 44 throttles, so that liquid refrigerant is forced back into the ejector, after which the system again picks up pressure which causes the discharge valve to open, thereby to deliver refrigerant to the evaporator I3. It is to be understood, that when operating on liquid only, the centrifugal pump will generate a substantially higher pressure than needed to open the discharge valve, but as said pump begins to pump' the refrigerant liquid into the evaporator I3 as fast as it condenses.

The present invention also contemplates the provision of a ball type (or other suitable type) check valve generally designated by the numera! 68. This check valve is disposed directly between the condenser and evaporator conduits 29 and 3I and comprises the usual valve ball 69 which is disposed within a valve case 10 so as to prevent the refrigerant fluid from by-passing around the valve 28 whenever the pump is operating. However, whenever the pump ceases to operate altogether, the ball 69 will drop in the usual manner thereby to permit the refrigerant fluid Within the evaporator I3 to by-pass the valve 28 and run back into the condenser 21. Of course, this ball will not drop until the pressure differential between the high and low pressure sides of the system has dropped almost to zero and thus, this check valve does not alter the effectiveness or take the place of the bellows 31 which functions to increase and decrease the volumetric capacity of the high pressure side of the system in response to various changes in the pressure differential.

Referring particularly to Figs. 1 and 5, it is to be understood that the check valve ball 69 normally rests upon the open end portion of a pipe extension 88 which projects into the valve case 10. This extension 88 is provided about its peripheral portion with a plurality of openings or notches 89, 89 which permit the refrigerant fluid within the evaporator I3 and the conduit 3| to run back into the condenser 21 whenever the pump ceases to operate. Of course, as hereinabove noted, Whenever the pump is in operation, it will be effective to force the refrigerant through the condenser 21 and toward the evaporator I3. Such a movement of the refrigerant will force the check valve ball B9 upwardly so that it will forcibly engage the valve seat 90 so as to prevent any fluid from passing through the valve case 10 and into the conduit 3|.

Also provided with the refrigerating system of my invention is a temperature control means which will be effective to deenergize the motor 28 whenever the temperature Within the cold box I0 falls below a predetermined level. Furthermore, by the same token, this temperature control means will be effective to energize the motor whenever the temperature within the box rises above this predetermined level.

This temperature controlmeans may take the form of a thermostatic bulb 1I which may be placed in any appropriate portion of the cold chamber I 0. This thermostatic bulb may contain a refrigerant vapor or a liquid and vapor and is connected to a bellows unit 12 by means of an appropriate connecting tube 1I'. The bellows 12 is disposed within a control box 13 and has provided on one end thereof an upstanding pin 14 which engages the lower side of. an arm 15 which is pivotally mounted about a pin 16. Engaging the upper side of the arm 15 is a rod 11 which is biased downwardly by means of a coil spring 18. The other end of the arm 15 lengages one end of a switch arm 19 which is rockably mounted upon a pin 80. The other end of the arm 19 is provided with an electrical contact 8| which is normally spaced from a similar contact 8|' carried by a normally stationary adiusting screw 82. From this it is to be understood that Whenever the temperature rises within the cold box II), the vapor within the bulb 1I will expand thereby, in turn, to expand the bellows 12. As

I soon as the bellows are expanded upwardly in opposition to the balancing spring 18, the arm 15 will be effective to snap the electrical contacts 8| and iIl' together. By the same token, as soon as the temperature within the cold box l drops below a predetermined level, the nuids contained within the bulb 1| will contract with the result that the contacts 8| and 8|' will be snapped apart by means of the balancing spring 18. The contacts Il and 8| are effective to energize and deenergize the motor 20 for the reason that they are connected to one side of an electrical supply which is brought to the apparatus by means of wires Il. A throw switch 84 connects the electrical supply source with wires 85 and 86 of which the latter is connected directly to the motor 20. The other wire 85 is connected to the arml and the contact 8| is connected with the motor by means of a wire 81. From this it will be understood that as soon as contacts 8l and 8i' are in engagement, the motor 20 will be energized from the electrical supply source 83 and as soon as these contacts are opened, the motor will be immediately deenergized. Thus, this temperature control means will be effective to maintain the cold box I0 at a constant temperature at all times.

I claim:

1. In a refrigerating apparatus of the type described, an evaporator, a condenser, a centrifugal pump for forcing refrigerant through said condenser, an ejector connected in series with said centrifugal pump for drawing vapor from said evaporator, a normally closed connection between said condenser and said evaporator, a pressureresponsive valve which is adapted to open said connection in response to a predetermined pressure differential existing between the iiuids contained within said evaporator and said condenser, and a pressure-responsive element for materially increasing the volumetric capacity of the high pressure side of said apparatus before said valve can open.

2. In a refrigerating apparatus of the type described, an evaporator, a condenser, a centrifugal pump for forcing refrigerant through said condenser, an ejector connected in series with said centrifugal pump for drawing vapor from said evaporator, a normally closed connection between said condenser and said evaporator, and means responsive to a predetermined pressure differential existing between the uids contained within said evaporator and said condenser for increasing the volumetric capacity of the high pressure side of said apparatus before opening said connection between said condenser and said evaporator.

3. In a refrigerating apparatus of the type described, an evaporator of the flooded type, an ejector, a low pressure vapor-conducting conduit connecting said evaporator with said ejector so' that the latter element will draw vapor from said evaporator whenever refrigerant is circulated through said ejector, pumping mean for circulatlow pressure conduits thereby to maintain a substantially constant liquid refrigerant level within said flooded evaporator.

4. In a refrigerating apparatus of the type described, an evaporator, a condenser, a rst refrigerant-conducting means, connecting said condenser with said evaporator and forming a part of the high pressure side of said apparatus, an ejector, a second refrigerant-conducting means forming a part of the low pressure side o! said apparatus and connecting said evaporator with said ejector so that said ejector will drawvapor .from said evaporator whenever refrigerant is circulated through said ejector, centrifugal pumping means, conduits connecting said ejector and said pumping means so as to form a substantially unobstructed and closed circulatory system, means connecting said condenser with one of said conduits, refrigerant control means connected with said first refrigerant-conducting means between said condenser and said evaporator, means connecting said control means with said second refrigerant-conducting means, means associated with said control means and responsive to various predetermined pressure differentials existing between the fluids contained within the high and low pressure sides of said apparatus for increasing and decreasing the volumetric capacity of the high pressure side. of said apparatus, means responsive to predetermined variations in the pressure differential existing between said fluids for opening and closing said rst refrigerant-conducting means, and a check valve connected between said evaporator and said condenser so as to by-pass said control means, said check valve being eifective to place said evaporator and said condenser in direct communication with each other whenever the fluid pressure within the condenser drops below a predetermined quantity.

WARREN H. DE LANCEY.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATESI PATENTS Number Name Date 1,874,912 Crosthwait Aug. 30, 1932 1,893,171 Kagi Jan. 3, 1933 1,958,087 v Hoffman May 8, 1934 2,050,994 Dube Aug. 11, 1936 

